Completion axillary lymph node dissection not required for regional control in patients with breast cancer who have micrometastases in a sentinel node.

Hypothesis: Completion axillary lymph node dissection (ALND) is not required for regional control in patients with metastases in the sentinel lymph node (SLN).

Design: Prospective cohort study.

Setting: Urban teaching hospital.

Patients: Fifty patients with breast cancer who underwent breast-conserving surgery, had an SLN positive for metastasis, and did not undergo completion ALND.

Interventions: Breast-conserving surgery with SLN biopsy, breast irradiation, and systemic therapy.

Main Outcome Measures: Locoregional and distant recurrence and survival.

Results: The mean patient age was 57 years (range, 29-83 years). The mean tumor size was 1.9 cm (range, 0.4-5 cm). The mean number of positive nodes was 1.3 (median, 1; range, 1-2). Fourteen patients (30%) had macrometastases (>2 mm), and 33 patients (71%) had micrometastases. The mean duration of follow-up was 82 months (median, 79 months; range, 6-142 months). One patient with an SLN micrometastasis (1 of 33; 3%) and 1 patient with an SLN macrometastasis (1 of 14; 7%) developed an axillary recurrence with distant metastasis at 84 months and 28 months, respectively. There was 1 death (2%) not related to breast cancer.

Conclusions: Patients with SLN metastases who do not undergo ALND have a low incidence of regional recurrence. Axillary lymph node dissection is not necessary for regional control in patients with micrometastatic disease.